Elucidation of Inhomogeneous Heterojunction Performance of Al/Cu5FeS4 Schottky Diode With a Gaussian Distribution of Barrier Heights

Abstract

Here, we analyze inhomogeneities in the barrier height (BH) of Al/Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> FeS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> Schottky device from the electrical (I-V) measurements with a temperature range between 303 and 408 K. The temperature-dependent performance of our fabricated device is analyzed by using the thermionic emission (TE) theory. Some important diode parameters like BH (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bo</sub> ), ideality factor (η), and series resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</sub> ) are evaluated from the forward current-voltage characteristic curves. The calculated η and R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</sub> of the Schottky barrier diode (SBD) decrease, whereas the Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bo</sub> of the device increases with the increase in temperature. The value of Richardson constant (A*) for our material is obtained as 1.94×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> A cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> in the temperature range 303-408 K, which is found as much lesser than the theoretical value of 29.90 A cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> . The discrepancy of A* from the theoretical value has been well explained by TE theory with the assumption of Gaussian distribution (GD) of BHs due to the existence of BH inhomogeneities at metal semiconductor (MS) junction. The obtained values of the mean BH Φ̅ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b̅o̅</sub> and the standard deviation σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> are 1.026 eV and 173 mV in the corresponding temperature range. The mean BH (1.199 eV) and Richardson constant (29.73 Acm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ) are determined from the modified Richardson plot depending on the inhomogeneity of BHs. Apparent BH consists of mean BH (Φ̅ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b̅o̅</sub> ) and standard deviation (σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ). The σ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> contributes significantly to the modification of Richardson constant and mean BH. The calculated value of the modified Richardson constant is in close agreement with the theoretical value. From C-V measurements built-in voltage and effective BH of this structure were calculated as a function of frequency.